Hyperthyroidism

Question 1

Definition

Answer 1

Hyperthyroidism is characterised by the overproduction of thyroid hormones by the thyroid gland

Subclinical hyperthyroidism is low TSH levels but regular T3/T4 levels

Thyrotoxicosis: a hypermetabolic condition caused by an inappropriately high level of circulating thyroid hormones irrespective of the source

Question 2

Epidemiology

Answer 2

Overt hyperthyroidism: ∼ 1%
Subclinical hyperthyroidism: 2–3%

Female : Male = 5:1

Graves disease: 20–30years
Toxic adenoma: 30–50years
Toxic MNG: peak incidence > 50years

Question 3

Pathophysiology

Answer 3

Disorders of the thyroid gland

• Excess production of T3/T4
• Compensatory decrease of TSH

Other

• Increased production of TSH or TSH imitating antibodies
• Increased T3/T4 levels

Question 4

Etiology

Answer 4

Graves disease (60–80% of cases)
Toxic MNG (15–20% of cases)
Toxic adenoma (3–5% of cases)
TSH-producing pituitary adenoma
Excessive Iodine intake (particularly if from an area of low iodine intake)

Question 5

Presentation

Answer 5

Signs

• Wight loss
• Irregular pulse
• High heart rate
• Hyperreflexia
• Goitre*
• Thyroid eye

Symptoms

• Anxiety
• Heat Intolerance
• Bowl frequency

Question 6

Lab Work Up

Answer 6

First line:
- Thyroid function test

Follow up:
TSH receptor antibody (TRAb) - Graves

Question 7

Imagining

Answer 7

Thyroid scintigraphy:
- Diffuse uptake of radioactive Iodide - Toxic MNG
Thyroid ultrasound - Pregnant patients

Question 8

Complications

Answer 8

Osteoporosis
- Excessive T4 speeds up the work of osteoclasts
- Osteoblasts don’t keep up
Thyrotoxic crisis
- Sudden increase in T3/T4 levels leading to systemic acute illness
Heart Disorders
Pregnancy Issues

Question 9

Differential Diagnosis

Answer 9

Neuropsychiatric symptoms - anxiety/panic disorders
Hyperadrenergic symptoms- intoxication with anticholinergics or cocaine/amphetamine misuse
Weight loss - diabetes mellitus or malignancy
Cardiac symptoms - congestive cardiac failure

Question 10

Treatment

Answer 10

Antithyroid drugs
               *Carbimiazloe
               *Proplythiouracil
Radioactive Iodine Ablation 
Surgery
Treatment of cardiac symptoms:
- Beta blockers

Question 11

Prognosis

Answer 11

50% remission for pharmacological treatment

Generally good when managed correctly

Can be fatal if left untreated (complications)

Question 12

Histology

Answer 12

Varies on Etiology